1. Field of the Invention
This invention concerns coal gasification in general and, more specifically, deals with an extruder for general application where the material extruded is a finely divided solid that is repulverized upon exit from the extruder. It also concerns a method of using an extruder for introducing pulverized solids to a high pressure reactor.
2. Description of the Prior Art
Extruders per se are, of course, well known for various uses, e.g. the U.S. Pat. Nos. 3,950,122 and 4,021,523. And, screw feed pumps (in the nature of extruders) have been suggested for feeding coal in a gasification process, as exemplified by U.S. Pat. No. 3,775,071. But, the latter involved a plurality of stages of feeding the coal in the form of a slurry, which was done in order to feed powdered coal into a high pressure reactor. However, such arrangements have not dealt with the need for a simple yet workable feeding arrangement for continuously feeding powdered coal into a high pressure reactor, particularly for coal gasification or the like reaction, therewith.
Extruder type structures have been suggested in U.S. Pat. Nos. 3,862,594 and 3,976,548 for feeding solid materials into a high pressure chamber. However, they have involved a mechanical chopping of the compacted solids, in the one case, or heating to plastic-like condition of the solids in the other case. Consequently, neither of these arrangements is without its drawbacks.
Thus, it is an object of this invention to provide an extruder combination for feeding a finely divided solid and using a gas at the exit of the extrusion to repulverize the solids in a high pressure atmosphere.
Another object of the invention is to provide a procedure for charging finely divided solids continuously into a high pressure reactor, in a novel manner. The combination provides for containing a high pressure by the inherent action of an extruder, while repulverizing the solids for use in a reaction in the container.